Cleaned up CCI details output

Closes #48
Cleans up create and create --test options
Unified testing output
format_output now only returns strings
FormatedItem now accepts an empty string as valid output
Adds SequentialOutput class
sl cci detail now handles missing data
Adds NestedDict helper for CLI
sl cci details now uses NestedDict
Removed NestedDict math ops, added tests
Removed useless tests for NestedDict
With - Style
Merge pull request #50 from CrackerJackMack/cci_cleanup

Cleaned up CCI details output